Biological treatment of dairy wastewater was investigated using a laboratoryscale
aerobic sequencing batch flexible fibre biofilm reactor (SBFFBR). The
SBFFBR system was modified from a typical sequencing batch reactor (SBR)
system by using eight simple flexible fibre bundles with a very high specific
surface area, which served as a support for bacteria. The 8 litre Perspex flexible
fibre reactor was developed for efficient and cost effective treatment of milk
industry effluent. A fine bubble air diffuser supplied oxygen in the reactor. Raw
dairy wastewater was fed to the reactor under different dilutions. The reactor was
operated under different influent COD concentrations (610, 2041 and 4382 mg/l)
and constant hydraulic retention times (HRT) of 1.6 days. The results have
shown successful applicability of the SBFFBR system, indicating high COD
removal efficiencies between 89.7% and 97% at average organic loading rates of
0.42 kg COD/m3.d and 2.74 kg COD/m3.d, respectively. Easy operation, low cost
and minimal sludge production were some of advantageous of the process.
Keywords: wastewater treatment, biofilm reactor, flexible fibre packing, milk
industry wastewater, sequencing batch reactor.
1 Introduction
The high cost of wastewater treatment for food industry wastes and increasingly
stringent effluent regulations have increased interest in alternative treatment
methods. The selection of a biological treatment process is based on the quality
of effluent needed, type of wastewater, and costs of operation [1, 2]. The
wastewater from food processing industries, such as milk processing, produce
considerable quantities of wastewaters, characterised by high concentrations of